Panel for sheathing system and method

ABSTRACT

The panel includes a water resistant barrier layer secured atop its outward facing surface. The water resistant barrier layer includes a skid resistant surface. The panels are made of lignocellulosic material. The water resistant and skid resistant surface may include indicia for aligning strips of tape or for aligning fasteners. A method for manufacturing the water resistant building panels is also disclosed and includes the steps of feeding paper onto a forming belt, depositing lignocellulosic material and the binding agent onto the forming belt so as to form a lignocellulosic mat, applying heat and pressure so as to impart the skid resistant surface on the paper, and cutting panels to predetermined sizes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/326,401, filed Dec. 15, 2011, which is a continuation of U.S. Pat.No. 8,112,950 issued Feb. 14, 2012. The '950 patent is a continuation ofU.S. Pat. No. 7,877,938 issued Feb. 1, 2011, which is a continuation ofU.S. Pat. No. 7,658,040 issued Feb. 9, 2010, which claims the prioritybenefit of U.S. Patent Application No. 60/547,029 filed Feb. 23, 2004,and U.S. Patent Application No. 60/547,031 filed Feb. 23, 2004. The '950patent is also a continuation of U.S. Pat. No. 7,870,694 issued Jan. 18,2011, which is a continuation of U.S. Pat. No. 7,721,506 issued May 25,2010, which claims the priority benefit of U.S. Patent Application No.60/547,029 filed Feb. 23, 2004, and U.S. Patent Application No.60/547,031 filed Feb. 23, 2004. And the '950 patent is acontinuation-in-part of U.S. Pat. No. 7,866,100 issued Jan. 11, 2011,which is a continuation of U.S. Pat. No. 7,677,002 issued Mar. 16, 2010,which claims the priority benefit of U.S. Patent Application No.60/547,029 filed Feb. 23, 2004, and U.S. Patent Application No.60/547,031 filed Feb. 23, 2004. The disclosures of all of the abovepriority documents are incorporated herein by reference for allpurposes.

FIELD OF THE INVENTION

The present invention relates to sheathing systems and, moreparticularly, to sheathing systems for roofs and walls utilizingmoisture resistant and skid resistant panels.

BACKGROUND

The roof of a residential or commercial building is typicallyconstructed by attaching several roofing panels to the rafters of anunderlying supporting structural frame; the panels are most often placedin a quilt-like pattern with the edge of each panel contacting the edgesof adjacent panels so as to form a substantially continuous flat surfaceatop the structural frame.

However, problems with roofs constructed according to this method maypresent themselves. In particular, small gaps along the edges ofadjoining roofing panels remain after roof assembly. Because the roofingpanels are typically installed days or even weeks before shingles areinstalled, it is important to have a panel system that minimizes leakageresulting from exposure to the elements until such time as the roof iscompleted. To prevent water from leaking through the gaps betweenpanels, it is commonly known in the industry to put a water resistantbarrier layer on top of the roofing panels (e.g., felt paper).Accordingly, there is a need in the art for roofing panels, which can beconveniently fit together and yet are constructed to minimize the gapsor allow the gaps to be sealed between adjacent roofing panels toprevent or minimize the penetration of bulk water through the roof as ittravels over the roof's surface. It is desirable for roofing panels toshed precipitation, such as rain and snow, during construction so thatthe interior remains dry.

While it is important that the barrier layer shed bulk water, it shouldalso allow for the escape of water vapor. If the barrier were to trapwater vapor in a roofing panel, the build-up of moisture could lead torot or mold growth that is undesirable. As mentioned previously, it isknown in the art that substantial bulk water-impermeability of installedroofing panels is achieved by adding a layer of impermeable material,such as asphalt-impregnated roofing paper or felt over the externalsurface of the roof panels. However, while this provides additionalprotection against bulk water penetration, it has the disadvantage ofbeing difficult and time-consuming to install because the paper or feltmust be first unrolled and spread over the roof surface and then securedto those panels. Further, the use of a felt paper overlay often resultsin a slick or slippery surface, especially when wet. Additionally, whenthe felt paper is not securely fastened to the roof panels or becomesloose due to wind and other weather conditions or because of poorconstruction methods, the roof system can become very slippery and leakbulk water. Accordingly, a worker walking atop the felt paper must becareful to avoid slipping or sliding while thereon. To that end, thepresent invention provides a panel for a roof sheathing systemcomprising structural panels, a mass-transfer barrier, and seam sealingmeans that is advantageously bulk water resistant and that exhibitsadequate anti skid characteristics.

In addition to roof panel systems, wall panel construction systems ofresidential or commercial buildings do not typically provide simple,efficient, and safe means of installation. Known wall systems arefrequently slick and do not provide adequate traction to securelysupport a ladder leaning thereon. Further, most often in these systems,an extra step must typically be added to the installation process toprevent liquid moisture and air from passing through the wall.Specifically, constructing a wall with a weather barrier requires notonly that panels be attached to framing members, but also a house wrapis unrolled and spread over the walls. The house wrap is attached to thesheathing panels with staples or button cap nails and fenestrationopenings for windows or doors must be cut out of the wrap and the flapsfrom these openings folded back and stapled down. The house wrap isoften difficult to install because it is typically in nine-ft widerolls, which can be difficult to maneuver by workers on scaffolding orin windy conditions. Accordingly, there is also need in the art forwall-sheathing panels, which are moisture vapor permeable,skid-resistant and which create a simplified, safe, and time-savinginstallation process by means of a surface overlay member or coatingpermanently bonded thereon. To that end, the present invention alsoprovides a panel for a wall sheathing system comprising structuralpanels, a mass-transfer barrier, and seam sealing means.

Accordingly, another general object of this invention is to provide awall system that provides a barrier to bulk water, water vapors, air andheat transfer, irritants, insects and mold that can be permeable tomoisture movement and is suitable for use behind numerous exteriorfinishes, such as siding, EIFS, brick, stucco, lap siding, vinyl, andthe like.

Furthermore, the wall assembly consists of a simple process. Panels areaffixed with a barrier layer and fastened to a building frame in aside-by-side manner, with or without a tongue and groove connection.Next, a sealing means, such as tape, laminate, caulk, foam, spray,putty, mechanical means, or any other suitable sealing mechanism, isused to seal the joints or seams between adjoining panels, thuscompleting the moisture barrier.

Given the foregoing, there is a continuing need to develop improvedpanels for roof and wall construction that prevent or minimize thepenetration of bulk water, that come pre-equipped with a water permeablebarrier layer applied during manufacture, and that have a skid resistantsurface.

The foregoing summary, as well as the following detailed description ofpreferred embodiments of the invention, will be better understood whenread in conjunction with the appended drawings. For the purpose ofillustrating the invention, there is shown in the drawings embodimentswhich are presently preferred. It should be understood, however, thatthe invention is not limited to the precise arrangements andinstrumentalities shown in the drawings, and that for purposes ofillustration, these figures are not necessarily drawn to scale.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a panelized roofing system utilizing thepanel of the present invention.

FIG. 2 is an exploded perspective view of a first embodiment of onepanel of the present invention.

FIG. 3 is a view of a panel and barrier layer according to the presentinvention.

FIG. 4 is an exploded perspective view of a panel, showing a detailedexploded view of the textured surface, according to the presentinvention.

FIG. 4A is a cross-sectional view of the textured surface taken alongthe line 4A-4A of FIG. 4.

FIG. 5 is a partial cross-sectional view of two adjacent panelsaccording to one embodiment of the present invention.

FIG. 6 is a perspective view of a panel according to an embodiment ofthe present invention.

FIG. 7 is a perspective view of a three-dimensional wall sheathingsystem utilizing the panel according to another embodiment of thepresent invention showing adjacent wall panels with lengths of tapesealing the joints therebetween, each of the lengths of tape overlappingat least one of the joints.

FIG. 8 is an exploded view of an embodiment of the structural panelaccording to the present invention and a view of the glueline forpermanent bonding of the surface overlay member to the panel.

FIG. 9A is a partial cross-sectional view of two adjacent panelsaccording to one embodiment of the present invention withtongue-and-groove connected panels after seam sealing.

FIG. 9B is a cross-sectional view of two adjacent panels according toone embodiment of the present invention in a wall sheathing system withedge abutting connected panels after seam sealing.

FIG. 10 is a flow diagram of the steps included in the manufacture of apanel for roof or wall sheathing system according to the presentinvention.

FIG. 11 is a plan view of a panel, according to the invention.

FIG. 12A is a partial plan view of a pair of panels; each according tothe invention, aligned for engagement.

FIG. 12B is a partial plan view of a pair of panels, each according tothe invention, engaged.

FIG. 13 is a diagram of box plots showing the differences in thecoefficient of friction between paper overlaid wood composite panelswith smooth and textured surfaces, oriented strand board with a texturedsurface, oriented strand board with a sanded surface and plywood in thedry condition.

FIG. 14 is a diagram of box plots showing the differences in thecoefficient of friction between paper overlaid wood composite panelswith smooth and textured surfaces, oriented strand board with a texturedsurface, oriented strand board with a sanded surface and plywood in thedry condition.

FIG. 15 is a diagram of box plots showing the differences in thecoefficient of friction between paper overlaid wood composite panelswith a smooth and textured surface and plywood in the wet condition.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

All parts, percentages and ratios used herein are expressed by weightunless otherwise specified. All documents cited herein are incorporatedby reference.

As used herein, “wood” is intended to mean a cellular structure, havingcell walls composed of cellulose and hemicellulose fibers bondedtogether by lignin polymer.

“Wafer board” is intended to mean panels manufactured from reconstitutedwood wafers bonded with resins under heat and pressure.

By “wood composite material” it is meant a composite material thatcomprises wood and one or more other additives, such as adhesives orwaxes. Non-limiting examples of wood composite materials includeoriented strand board (“OSB”), waferboard, particleboard, chipboard,medium-density fiberboard, plywood, and boards that are a composite ofstrands and ply veneers. As used herein, “flakes” and “strands” areconsidered equivalent to one another and are used interchangeably. Anon-exclusive description of wood composite materials may be found inthe Supplement Volume to the Kirk-Othmer Encyclopedia of ChemicalTechnology, pp. 765-810, 6^(th) edition.

As used herein, “structural panel” is intended to mean a panel productcomposed primarily of wood which, in its commodity end use, isessentially dependent upon certain mechanical and/or physical propertiesfor successful end use performance such as plywood. A non-exclusivedescription may be found in the PS-2-92 Voluntary Product Standard.

The following describes preferred embodiments of the present inventionwhich provides panels for a panelized roofing system, attached to therafters of a timber frame structure to form a roof, and that is suitablefor use in the construction of residential and commercial buildings. Inaddition, an alternate embodiment of the present invention, whichprovides panels for a panelized wall sheathing system that is suitablefor use in the construction of residential and commercial buildings isshown and described.

Use of Panel for Roof Sheathing

FIG. 1 illustrates a panelized roof sheathing construction system 10 fora building having a plurality of panels 20 attached to a building framestructure in substantially abutting relationship. The panels 20 have aninward facing surface 22, an outward facing surface 24 and at least oneperipheral edge. The system 10 also includes a plurality of waterresistant barrier layers 30 adhesively secured to at least one of thesurfaces 22, 24 of the panels 20, each barrier layer 30 providing asubstantially skid-resistant and bulk water resistant surface. Oneexample of a paper overlaid wood board is shown and described in U.S.Pat. No. 6,737,155 entitled “Paper Overlaid Wood Board and Method ofMaking the Same” which is incorporated herein by reference.Additionally, the system 10 preferably includes a plurality ofwater-resistant sealing means 40, each of the means 40 sealing at leastone of the joints 25 between the adjacent panels 20.

The panels 20 prepared according to the present invention may be madefrom a variety of different materials, such as wood or wood compositematerials. As shown in FIG. 2, the panels 20 are preferably comprised ofan oriented strand board substrate (“OSB”) having at least two surfaces22, 24 with at least one core layer 26 disposed between them. OSB panelsare derived from a starting material that is naturally occurring hard orsoft woods, singularly or mixed, whether such wood is dry (preferablyhaving a moisture content of between 2 wt % and 12 wt %) or green(preferably having a moisture content of between 30 wt % and 200 wt %)or of moisture content in between dry and green (preferably having amoisture content of between 12 wt % and 30 wt %). Typically, the rawwood starting materials, either virgin or reclaimed, are cut intoveneers, strands, wafers, flakes, or particles of desired size andshape, which are well known to one of ordinary skill in the art.

Each of the surface layers 22, 24 of the panel 20 are preferablyoriented in parallel with the long dimension of the panel 20, and theoriented strand board core 26 preferably includes a plurality ofsubstantially parallel strands 23 that are oriented perpendicular to thestrands of the surface layers 22, 24. The panels 20 of the panelizedroof system 10 may be selected from a number of suitable materials thatprovide adequate protection against the penetration of bulk water.Preferably, the panels of the present invention are comprised ofreconstituted lignocellulosic furnish. More preferably, the panels 20are comprised of structural wood such as OSB or plywood. Types of woodmaterial used to manufacture the panels 20 may be, but are not limitedto particle board, medium density fiber board, waferboard or the like.

The presently described panels 20 are preferably of a thickness T in arange from about 0.635 cm (0.25 inches) to about 3.175 cm (1.25 inches).The panels 20 may also comprise a radiant barrier material attached tothe lower face of the panel, i.e., the face of the panel facinginwardly, toward the interior of the building. The radiant barriermaterial preferably includes a reflective surface that reflects infraredradiation that penetrates through the roof back into the atmosphere. Thecombination of this reflective function, as well as the foil's lowemissivity, limits the heat transfer to the attic space formed in theinterior of the building in the space under the roof. By limiting theheat transfer, the attic space temperature is reduced, which in turnreduces the cost of cooling the house.

The radiant barrier material may simply be a single layer radiantbarrier sheet, such as metal foil, such as aluminum foil. Alternatively,the radiant barrier material may be composed of a radiant barrier sheetadhered to a reinforcing backing layer made from a suitable backingmaterial, such as polymeric film, corrugated paper board, fiber board orkraft paper. The backing material makes the foil material easier andmore convenient to handle. The multi-layered material may be a laminatein which a backing material is laminated to a radiant barrier sheet.

Methods of manufacturing the radiant barrier material are discussed ingreater detail in U.S. Pat. No. 5,231,814, issued Aug. 3, 1993 toHageman and U.S. Pat. No. 3,041,219, issued Jun. 26, 1962, to Steck etal. Other suitable radiant barrier material is manufactured under thename SUPER R™ by Innovative Insulation, Inc. of Arlington, Tex. TheseSUPER R™ products have two layers of aluminum foil each of which have analuminum purity of 99%, and a reinforcing member located inside, betweenthe two layers. The reinforcing member may be a reinforcing scrim or apolymer fabric.

Both the radiant barrier material and the barrier layer can be appliedto the panel by spreading a coat of adhesive to the surface of thepanel, applying the heat-reflecting material (or the barrier layer) overthe adhesive onto the panel and pressing the radiant barrier material(or barrier layer) onto the panel. After the adhesive dries or cures,the panel is ready for use.

Additionally, the radiant barrier may be a coating on either side of thepanel 20, which could be used facing into or out from the attic.Additionally, some panels 20 may also provide protection againstultraviolet light per ASTM G53, G154, which does not delaminate, doesnot reduce slip resistance, and does not promote fading.

Referring now to FIG. 3, the panel for the panelized roof or wall system10 includes a barrier layer 30 secured to the outward facing surface ofpanel 20, with each barrier layer 30 providing a substantiallyskid-resistant surface 35.

These barrier layers 30 may optionally be comprised of aresin-impregnated paper 32 having a paper basis weight of 21.772 kg (48lbs.) to about 102.058 kg (225 lbs.) per ream or a dry weight of about78.16 gm/m² (16 lbs./msf) to about 366.75 gm/m² (75 lbs./msf), and theypreferably substantially cover the outward facing surface 24 of thepanels 20. The paper 32 is preferably resin-impregnated with a resinsuch as, but not limited to a phenol-formaldehyde resin, a modifiedphenol-formaldehyde resin, or other suitable resin. Preferably, thepaper has a resin content of about greater than 0% to about 80% by dryweight, most preferably from a range of about 20% to about 70% by dryweight. The resin-impregnated paper for the panel in the panelized roofor wall sheathing construction system of the present invention alsopreferably includes a glueline layer 50 in a range from about 9.77 gm/m²(2 lbs./msf) to about 244.5 gm/m² (50 lbs./msf), and more preferably ofa range from about 9.77 gm/m² (2 lbs./msf) to about 177.24 gm/m² (12lbs./msf). The glueline layer 50 may be formed from aphenol-formaldehyde resin, and isocycanate, or the like.

Further optionally, the barrier layer may comprise an applied coatinglayer. One such coating is an experimental acrylic emulsion coating fromAkzo-Nobel. Another suitable coating is Valspar's Black Board Coating.It is understood that by those skilled in the art that other classes ofcoatings may serve as an appropriate barrier layer. Coatings may be usedwith paper overlays to add the desired functions to the panel.

The barrier layer 30 is resistant to bulk water but permeable to watervapor. These panels with barrier layers 30 are optionally characterizedby water vapor permeance in a range from about 0.1 U.S. perms to about1.0 U.S. perms, and have a water vapor transmission rate from about 0.7to about 7 g/m²/24 hrs (at 73° F.—50% RH via ASTM E96 procedure A), andhave a water vapor permeance from about 0.1 to about 12 U.S. perms (at73° F.—50% RH via ASTM E96 procedure B), and a liquid water transmissionrate from about 1 to about 28 (grams/100 in²/24 hrs via Cobb ring), perASTM D5795. This test method allows the quantification of liquid waterthat passes through the underlayment to the underlying substrate and canbe easily done on specimens where the underlayment cannot be removed forvisual inspection.

An embodiment of this invention suggests that a non-skid surface thathas a coefficient of friction equal to or better than plywood ororiented strand board when dry and/or wet can be achieved in a primaryprocess that is both quick and relatively inexpensive. Specifically, thewater-resistant barrier layers 30 of the present inventionadvantageously provide a textured surface 35 to the structural panels20. Specifically, the textured surface 35 is adapted to provide a wetcoefficient of friction in a range of from about 0.8 to about 1.1(English XL Tribometer) and a dry coefficient of friction in a range offrom about 0.8 to about 1.1 (English XL Tribometer). Examples ofmethodology used to measure wet surfaces may be found at pg. 173 in“Pedestrian Slip Resistance; How to Measure It and How to Improve It.”(ISBN 0-9653462-3-4, Second Edition by William English).

Referring now to FIG. 4A, the textured surface 35 is characterized by anembossed pattern of features or indentations. As used herein,“embossing” can mean embossing, debossing, scoring, or any other meansto alter the texture of the panel other than adding grit or the like tothe surface.

The texture preferably has a number of features or elements disposed ina first direction and a number of features or elements disposed in asecond direction. For example, a first group of elements may be disposedin a direction across the width of a panel and a second group ofelements may be disposed in a direction along the length of a panel.These elements or features disposed in first and second directions maybe of similar or may be of different sizes. The elements similarly maybe of different or of similar shapes. Non-limiting examples of similarlysized features include a embossed herringbone or a embossed basketweaveconfiguration. A herringbone pattern may be very tightly disposed or maybe somewhat “spread-out” in such a manner so that major channels withminor indentations are created.

The embossed textured surface preferably is more preferably comprised ofa plurality of major or primary textured features and a plurality ofminor or secondary textured features. Preferably, the minor or secondarytextured features are at least partially disposed on one or morecorresponding major feature. To illustrate, and although the generalappearance of the preferred textured surface 35 appears to be a randompattern of raised areas, a closer examination of the preferred texturedsurface reveals finer detail. Specifically, the preferred texturedsurface 35 includes a plurality of major channels 33 that are disposedsubstantially parallel with a pair of opposing edges (preferably theshorter pair of opposing edges) of the panel. Additionally, a pluralityof minor indentations 34 are disposed within the major channels 33 andrun generally orthogonally to the major channels. It should beappreciated that the exploded magnified view of FIG. 4, showing theminor indentations 34 and major channels 33 in detail, is illustrativeand does not necessarily represent the preferred density of minorindentations or major channels.

Although it is within the scope of the present invention to provide foradvantageous slip-resistance by providing any number of major channels,preferably, the density of the major channels is about 5 to about 15major channels per 2.54 cm (inch) as measured in a directionperpendicular to the direction of the major channels. More preferably,the density of the major channels is about 9 to about 12 major channelsper 2.54 cm (inch) as measured in a direction perpendicular to thedirection of the major channels. On a typical 1.219 m×2.438 m (4′×8′)sheathing panel, the major channels will preferably run generally acrossthe 1.219 m (four-foot) or short direction. It should be appreciatedthat it is not necessary nor required that the major channels be exactlyparallel and may undulate slightly from side to side in a somewhatserpentine fashion rather than being straight.

Although it is within the scope of the present invention that the minorindentations 34 may vary in length and width, the minor indentations 34have a preferably elongated shape that measures preferably about 0.0508cm (0.020 inches) to about 0.254 cm (0.100 inches) in length and about0.0254 cm (0.010 inches) to about 0.254 cm (0.100 inches) wide. Althoughit is within the scope of the present invention to provide foradvantageous slip-resistance by providing any number of minorindentations, preferably, the density of the minor indentations is about15 to about 35 of the minor indentations per inch as measured along thedirection of the major channels. The long direction of the minorindentations preferably extends generally across the eight-foot (orlong) direction of a typical panel.

The textured surface may also, alternatively, be created via a pluralityof raised protrusions and grooves. The protrusions may have a height ina range of about 0 mils to about 25 mils, preferably from a range ofabout 3.0 to about 13.0 mils as measured by profilometry (MitutoyoSJ201P).

In accordance with the preferred configuration of the textured surface35, in a typical roof sheathing application using 1.219 m×2.438 m(4′×8′) panels where the 2.438 m (eight-foot) edge of the sheathingpanel is parallel to the floor of the home, the major channels 33 willgenerally be oriented up and down, while the long direction of the minorindentations 34 will generally run across the roof. Preferred depth ofthe major channels and minor indentations have been found to be in arange of about 5 to about 13 mils as measured by the Mitutoyo SurfaceProfiler. It should be appreciated that at least some of the majorchannels and minor indentations may be of a depth greater or deeper thanthe thickness of the paper (i.e., some of the major channels and minorindentations may be of a depth that would project into the surface ofthe panel).

The anti-skid surface of the present system advantageously reduces thepotential for a ladder leaning thereon to slip. A worker who is applyinghouse wrap or taping house wrap is currently exposed to the risk of hisladder skidding against the slippery surface of house wrap. Currenthouse wrap products create the opportunity for a worker to fall from aladder that skids against house wrap. The surface of current house wrapproducts promotes the likelihood of “ladder slip.” Workers havecomplained that ladders will slide unless they apply a skid resistantproduct to their ladders

As shown in FIG. 3, the barrier layers 30 may further include indicia 37for positioning fasteners. U.S. Pat. App. Pub. 2003/0079431 A1 entitled“Boards Comprising an Array of Marks to Facilitate Attachment”,incorporated herein by reference, provides additional detail regardingfastener indicia 37. Additionally, the barrier layers are preferablyadapted to receive fasteners in a substantially moisture-proof manner.

FIG. 5 illustrates the cross-sectional profile of a further aspect ofthe panel for a panelized roof or wall sheathing construction system 10.When attached to a building frame, joints 25 form between the panels 20.Particularly, shown is a water-resistant sealing means comprised ofstrips of water-resistant tape 42 with backing 44 and an adhesive layer46. Each of the strips of tape 42 may be applied by a hand held tapeapplicator to at least one joint between adjacent panels 20 to form asubstantially moisture-resistant seam with roofing accessory materialssuch as skylights, ventilation ducts, pipe boots, felt, flashing metals,roofing tapes, and various building substrates. The tape 42 of thepresent invention may have no backing or a backing 44 with a thicknessof about ½ to about 1/30 the thickness of the adhesive layer 46.Optionally, the strips of tape 42 may have a backing of a thickness ofabout 1.0 mils to about 4.0 mils and an adhesive layer disposed on thebacking of a thickness of about 2.0 mils to about 30.0 mils. The drycoefficient of friction for the tape is preferably of at least about0.6. As shown in FIG. 3, alignment guides 43 on the panel for applyingthe tape strips 42 are also contemplated to facilitate installation.Preferably, the alignment guides 43 are placed approximately a distanceof about ½ the width of the tape from the panel edge. The tape strips 42are preferably installed by means of a handheld tape applicator.

The panels 20 of the panelized roof sheathing construction system 10preferably have a first edge which is parallel with a correspondingsecond edge of a panel 20 and are preferably linked together via one ofa tongue 27 and groove 28 configuration (FIG. 5), an H-clipconfiguration, or a mating square edge configuration, as would beunderstood by one skilled in the art.

Referring now to FIG. 6, each of the first and second edges preferablyhave contiguous sections of equal length, with each section potentiallyincluding a groove 28 and a tongue 27 compatible with a correspondinggroove 28 (and tongue 27). An example of one such tongue and groovepanel is shown and described in U.S. Pat. No. 6,772,569 entitled “Tongueand Groove Panel” which is incorporated herein by reference.

Another such example is shown and described in U.S. patent applicationSer. No. 10/308,649 entitled “Composite Wood Board having an AlternatingTongue and Groove Arrangement along a Pair of Edges” which isincorporated herein by reference. The length of the first edge of eachpanel 20 is preferably a multiple of the length of a section, with themultiple being at least two. The length of the tongue 27 in each sectionmeasured in the longitudinal direction of an edge is preferably lessthan or equal to the length of the grooves 28, or the longest groove 28in each section.

Referring to FIG. 11, panel 20 may have a first edge A, a second edge B,a third edge C and a fourth edge D. Edges A and B may be parallel. EdgesC and D may be parallel and substantially perpendicular to edges A andB. Each of the edges A and B of panel 20 may include an alternatingtongue and groove arrangement. Specifically, edge A includesperpendicularly extending tongues 27 and grooves 28. Edge B is similarlyconstructed. It includes tongues 27 and grooves 28. Edge C is in contactwith tongue 27 of edge B and groove 28 of edge A. Edge D is in contactwith groove 28 of edge B and tongue 27 of edge A. Thus, the tongues andgrooves of panel 20 are directly opposite each other.

Referring to FIGS. 12A and 12B, the tongues 27 and grooves 28 along edgeA of panel 20 can be brought into engagement with the grooves 28 andtongues 27 of edge B of adjacent panel 20. Similarly, if one of theboards 20 is rotated one hundred and eighty degrees, the tongues 27 andgrooves 28 along abutting edges can be brought into engagement.

As a general summary shown in FIG. 10, producing skid-resistant andwater-resistant building panels of the present invention comprises thesteps of providing a roll of dry paper, feeding a leading edge of asheet of paper from said roll of dry paper onto a forming belt, anddepositing reconstituted lignocellulosic furnish with an applied bindingagent atop the dry paper sheet so as to form a lignocellulosic mathaving first and second lateral edges. The flake mat and the dry papersheet are cut into a segment of a predetermined length. Preferably, thetop surface of the flake mat is compressed and the first and secondlateral edges of the flake mat are packed prior to the cutting step. Thesegments are transferred onto a loading screen and then into a hotpress. Sufficient heat and pressure are provided in order to set thepanel structure and to form a skid-resistant surface resulting from thescreen imprint on said paper. The segments are cut into panels ofpredetermined sizes. The paper sheet is preferably wet prior totransferring the segment onto the loading screen. Additionally, indicia37 for positioning fasteners or tape alignment guides 43 are preferablymarked onto the panel.

As a person becomes accustomed to walking on sloped surfaces such asroof systems, a small change in the coefficient of friction can causesomeone to easily lose his or her footing. This is illustrated in Table1, which shows the coefficient of friction of plywood, OSB, those panelswith securely fastened roofing felt and OSB and plywood with loose feltpaper applied. The significant differences seen in the coefficient offriction of systems between felt paper being securely fastened andloose, is more than enough to cause a slipping hazard. The presentsystem 10 has an advantage over felt paper in that the coefficient offriction does not change since the barrier layer 30 is securely fastenedto the panel 20 prior to installation thus virtually eliminating theoccurrence of paper coming loose in the field.

It is important that the panels used in roof applications are notslippery in service. It has also been observed that the coefficient offriction can vary among roof sheathing products of similar types fromdifferent sources. Further, the coefficient of friction of panels fromone manufacturer can change dramatically, such as when the panels getwet from a change in weather conditions or morning dew. Further, thechange in coefficient of friction can be inconsistent amongmanufacturers. This may be the result of process conditions, woodspecies, and raw materials used to manufacture these products. Sandingdoes not improve friction for sheathing panels even though it removes atop layer of wood that may be partially degraded by the processconditions, but it does promote adhesion for secondary lamination. Flatlaminated products are perceived to be more slippery than texturedproducts, and water on many substrates makes them slippery when wet. Ananti-skid coating can be added to improve the coefficient of friction,but these coatings add additional manufacturing steps, equipment, andcost. Indeed, when plywood or OSB panels are overlaid with paper tocreate a smooth surface, the coefficient of friction drops compared toregular plywood and OSB. Adding texture to the surface of OSB has beensuggested as a method of improving friction or skid-resistance of thesepanels, but testing of OSB sheathing using the English XL Tribometershowed that the coefficient of friction of the smooth and textured sidesof OSB were very similar under dry conditions and that the texture coulddecrease the coefficient of friction in the wet condition, which isshown in Table 2.

Thus, another notable advantage of the present invention is retainedskid resistance when wet. When texture is added to the surface of anoverlaid wood composite panel of the present invention, the coefficientof friction unexpectedly increased above that of standard plywood andOSB.

An embodiment of the present invention is illustrated in Tables 3 & 4and Plots 2 & 3, which shows the coefficient of friction of the screenimprinted overlaid panel vs. smooth overlaid panels, oriented strandboard with a screen imprint, oriented strand board that has been sandedand plywood in dry and wet conditions. Paper basis weights (per ream) of31.751 kg (70 lbs.), 44.906 kg (99 lbs.) and 59.874 kg (132 lbs.) werealso tested and compared to show that the range of paperweightsmentioned in the embodiment of this record of invention will satisfy thecoefficient of friction requirements.

From testing conducted using the English XL Tribometer, the coefficientof friction, as can be seen from Table 3, is significantly higher when ascreen imprint is embossed on the surface of the panels as compared tothe smooth surface of paper-overlaid panels. From Table 4, it can beseen that the coefficient of friction of the overlaid panels with thetextured surface does not significantly decrease when wet and is muchbetter than the coefficient of friction of plywood when wet.

As one example of this invention, a roll of Kraft paper of 44.9 kg (99lb.) basis weight (per ream), saturated to about 28% by weight resincontent with a glue line of phenolic glue of about 4.536 kg/304.8 m²(10-lbs/1000 ft²) applied to one side of the paper was mounted onto apaper feeding apparatus so that the paper could be fed onto the formingline of an oriented strand board.

The paper was then fed onto the forming line belt with the glue lineside of the paper facing up away from the belt. To prevent wrinkling ortearing of the paper, the paper roll must be un-wound at a speed that isconsistent with the speed of the forming line. To maintain completecoverage of the paper overlay onto the wood composite substrate, thepaper is aligned with the forming line belt as it carries the mat towardthe press.

Once the paper is fed onto the forming line, a wood mat is formed on topof the paper as it moves toward the press. The wood mat is formed withthe first and second layers being the surface layers composed of strandsoriented in a direction parallel to the long dimension of the panels anda third core layer composed of strands oriented in a directionperpendicular to the first and second layers.

TABLE 1 ANOVA table showing the differences in the coefficient offriction between common roofing panels of plywood and OSB and the use offelt that is securely fastened or loose on these panels. The coefficientof friction of the panel of a preferred embodiment is also shown forreference. Analysis of Variance for CoF Source DF SS MS F P Product  52.47230 0.49446 151.42 0.000 Error 66 0.21552 0.00327 Total 71 2.68782Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev

Embodiment 1 12 0.9043 0.0516          

Felt 12 0.9973 0.0233            

Loose felt¹ 12 0.5136 0.0323

Loose felt² 12 0.5646 0.0432  

OSB 12 0.7381 0.0771       

plywood 12 0.9360 0.0868            

Pooled StDev = 0.0571

¹Loose felt over OSB substrate. ²Loose felt over plywood substrate.

FIG. 13 illustrates box plots showing the differences in the coefficientof friction between paper overlaid wood composite panels with smooth andtextured surfaces, oriented strand board with a textured surface,oriented strand board with a sanded surface and plywood in the drycondition. “Level” is expressed as paper basis weight per ream foroverlay panels. CoF=Coefficient of friction.

TABLE 2 ANOVA table showing the differences in the slip angle betweenthe textured and smooth sides of OSB in the dry and wet condition andplywood in the wet and dry condition. The coefficient of friction isrelated to slip angle by CoF = Tan (slip angle), where the slip angle isexpressed in radians. Source DF SS MS F P Factor  5 232.33 46.47 12.460.000 Error 90 335.63  3.73 Total 95 567.96 Individual 95% CIs For MeanBased on Pooled StDev Level N Mean StDev

dry-plywood 16  42.000 0.177         

dry-Textured 16  41.500 0.530        

dry-Smooth 16  42.063 0.442         

wet-plywood 16  40.000 1.237     

wet-Textured 16  37.625 0.530

wet-Smooth 16  39.938 1.326     

Pooled StDev = 0.824

TABLE 3 ANOVA table showing the differences in the coefficient offriction between paper overlaid panels with a smooth surface and with atextured imprint as well as oriented strand board with a texturedimprint, oriented strand board sanded and plywood in the dry condition.“Level” is expressed as paper basis weight (in lbs.) per ream foroverlay panels. Analysis of Variance for CoF Dry Source DF SS MS F PProduct  8 0.90809 0.11351 16.4 0.000 Error 177 1.22522 0.00692 Total185 2.13331 Individual 95% CIs For Mean Based on Pooled StDev Level NMean StDev

132 lbs. Paper Smooth 23 0.9125 0.1045    

132 lbs. Paper Textured 20 1.0614 0.0269           

 70 lbs. Paper Textured 20 0.9882 0.0422       

 70 lbs. Paper Smooth 20 0.9106 0.1148    

 99 lbs. Paper Textured 20 1.0533 0.0319          

 99 lbs. Paper Smooth 24 0.9343 0.1079    

OSB Sanded 26 0.8391 0.1103

OSB Textured 17 0.9801 0.0428       

Plywood 16 0.9864 0.0666       

Pooled StDev = 0.0832

FIG. 14 illustrates box plots showing the differences in the coefficientof friction between paper overlaid wood composite panels with smooth andtextured surfaces, oriented strand board with a textured surface,oriented strand board with a sanded surface and plywood in the drycondition. “Level” is expressed as paper basis weight per ream foroverlay panels. CoF=Coefficient of friction.

TABLE 4 ANOVA table showing the differences in the coefficient offriction between paper overlaid wood composite panels with smooth andtextured surfaces and plywood in the wet condition. “Level” is expressedas paper basis weight per ream for overlay panels. Analysis of Variancefor CoF Wet Source DF SS MS F P Product  6 1.59735 0.26623 207.03 0.000Error 136 0.17489 0.00129 Total 142 1.77224 Individual 95% CIs For MeanBased on Pooled StDev Level N Mean StDev

132 lbs. Paper Smooth 23 0.8180 0.0373  

132 lbs. Paper Textured 20 1.0410 0.0294           

 70 lbs. Paper Textured 20 1.0125 0.0286          

 70 lbs. Paper Smooth 20 0.8003 0.0426

 99 lbs. Paper Textured 20 1.0386 0.0284           

 99 lbs. Paper Smooth 24 0.8039 0.0432  

Plywood 16 0.8882 0.0362     

Pooled StDev = 0.0359

CoF = Coefficient of friction.

FIG. 15 illustrates box plots showing the differences in the coefficientof friction between paper overlaid wood composite panels with a smoothand textured surface and plywood in the wet condition. “Level” isexpressed as paper basis weight per ream for overlay panels.CoF=Coefficient of friction.

During this process, flakes can be pushed underneath the paper overlayand can be pressed on to the surface of the panel, giving the panel alow quality look and hindering the performance of the final product.Therefore, air wands are used at the nose of the forming line to removethe excessive flakes between the paper overlay and the forming linebelt.

The mat is then cut into a predetermined size for placing into press.The cut mats are then moved over the nose on the forming line (where theflakes are removed from the paper's surface using the air wands) andpicked up by a screen embossed transfer mat. If appropriate, in theproduction of oriented strand board, the screen embossed transfer mat issprayed with a release agent to keep the flakes from sticking to thepress. However, given that there is a Kraft paper overlay between theflakes and the mat, the release agent is not needed. To prevent the woodmat from slipping off the transfer mat during acceleration, water issprayed on the surface of the transfer mat prior to the transfer matpicking up the wood mat.

The screen embossed transfer mat and wood mat are then placed in a hotpress at a temperature preferably greater than 360° F. for a period longenough to cure the binders on the wood flakes.

The transfer mat then moves the pressed master mat out of the press,removing the screen embossed transfer mat from the wood master mat,leaving an embossed pattern on the surface of the paper overlay. Theembossed pattern has hills and valleys with a distance between thevalleys and hills of preferably about 0.03048 cm ( 1/1000 inch) to about0.3048 cm ( 10/1000 inch). The pattern is enough to provide needed skidresistance without puncturing the paper overlay, compromising thewater-resistant quality of the panel.

Once the master mat is removed from the press, it can be cut into anydimension to meet the needs of the final user and the edges of thepanels sealed with an edge seal coating.

It is understood by those skilled in the art that a continuous presscould be used to manufacture overlay panels. One obvious change in themethod would be that mastermats would be cut to size after leaving thepress.

Use of Panel for Wall Sheathing

According to an alternate embodiment of the present invention, FIG. 7shows wall panels 120 joined to a building frame structure 115. Similarto the roof panels, the wall panels 120 have barrier layers bonded onone surface, and are generally attached to the building frame 115 insubstantially abutting relationship with a plurality of fasteners suchas nails, screws, or any other suitable fastener known on the art (notshown) so as to form joints therebetween. Also similar to the roofpanel, the wall panel also preferably comprises a textured surface asdescribed previously in the roof panel discussion.

Depending on the size of the panels 120 selected, the panels 120 may beinstalled with a horizontal or vertical orientation. In FIG. 7, panels120 are installed vertically and horizontally and may typically be, butare not limited to a 1.219 m×2.438 m (4 ft.×8 ft.) construction.Additionally, a panel may be 1.219 m×3.048 m (4 ft.×10 ft.), 1.219m×3.658 m (4 ft.×12 ft.), or of any desired size for the particularbuild.

As is well known in the field, the panels 120 may be structural, and maycomprise a wood composite, such as veneers, strands, wafers, particles,fibers, and binders, or may be made from any building grade material asrequired for the particular build. The preferred dimensions of the wallpanels 120, including the length L, width W, and thickness T of thepanel may be designed to fit the particular application. Optionally, aone half inch thick panel T is used, however a 0.635 cm (quarter inch)to 3.175 cm (1.25-inch) thick panel 120 or thicker may be used ifheavier construction is desired.

Turning now to FIG. 8, the structural panels 120 are quadrilateral inshape comprising an inward facing surface 121, an outward facing surface122 and a peripheral edge, the peripheral edge defining a first 123,second 124, third 125 and fourth 126 edge of the panel 120. The firstedge 123 of the panel is parallel with the corresponding third edge 125of the panel, each of the first 123 and third 125 edges having opposingsections of equal length, and the second edge 124 of the panel isparallel with the corresponding fourth edge 126 of the panel, each ofthe second 124 and fourth 126 edges having opposing sections of equallength. Further, the first 123 and third 125 edges of the panel aresubstantially perpendicular with adjacent second 124 and fourth 126edges. As illustrated in FIG. 9A, one or more of the edges of the panel120 may provide at least one tongue-and-groove 129 shape for joining andsecuring panels 120 together.

Where the tongue-and-groove configuration is utilized, opposing edgeshave a groove or tongue compatible with an opposing corresponding edgeand the length of the tongue in each section measured in thelongitudinal direction of an edge is less than or equal to the longestgrooves in each section. However, as shown in FIG. 9B, the panels 120may have flat surfaces 128 and be planar on all four peripheral edges123, 124, 125, 126.

As depicted in FIG. 8, a barrier layer 130 is comprised of a paper 132with at least two sides. During the construction stage of the panels120, a barrier layer 130 is bonded to each panel 120 to form thebarrier. Optionally, the bather layer 130 may comprise an UV-resistantoverlay, a radiant reflective layer or the like. The barrier layer 130is preferably comprised of three parts: paper 132, at least one of aresin 134 and a glueline layer 136, each of which may affect thedurability and the final permeability of the panel 120. Preferably, thepaper 132 has a paper basis weight of about 21.772 kg (48 lbs.) to about102.058 kg (225 lbs.) per ream or a dry weight about 78.16 gm/m² (16lbs./msf) to about 366.75 gm/m² (75 lbs./msf), however various basisweight papers 132 may be utilized for barrier layer 130. The paper 132is preferably resin-impregnated with a resin 134 such as, but notlimited to a phenol-formaldehyde resin, a modified phenol-formaldehyderesin, or other suitable resin. Preferably, the paper has a resincontent in a range of about 0% to about 80% by dry weight. Morepreferably, the paper has a resin content in a range of about 20% toabout 70% by dry weight. The resin 134 may be saturated on 152 and thenpartially cured 153 to the paper 132. This enables the paper 132 toretain the resin 134 and makes the resin-impregnated paper 132 easier tohandle.

Further optionally, the barrier layer may comprise an applied coatinglayer. One such coating is an experimental acrylic emulsion coating fromAkzo-Nobel. Another suitable coating is Valspar's Black Board Coating.It is understood that by those skilled in the art that other classes ofcoatings may serve as an appropriate barrier layer. Coatings may be usedwith paper overlays to add the desired functions to the panel.

An adhesive 136 is used to bond 155 the surface overlay member 130 tothe outward facing surface of each of the plurality of panels 120.Optionally, the adhesive 136 is a glueline applied to 154 one side ofthe barrier layer 130 to facilitate attachment to the panels 120 duringmanufacture. Preferably, a glueline layer 136 is of a range from about4.885 gm/m² (1 lbs./msf) to about 244.5 gm/m² (50 lbs./msf). Morepreferably, the glueline layer 136 has of a range from about 34.18 gm/m²(7 lbs./msf) to about 58.59 gm/m² (12 lbs./msf), creating a veryefficient and durable bond. As mentioned previously, the glueline layer136 may be composed from the group phenol-formaldehyde resin, hot-meltor PVA resin. Further optionally, the glueline layer may beisocynate-based.

As the plurality of resin-impregnated overlay bonded panels 120 areaffixed to a building frame 115 in substantially abutting relationship,joints or seams are formed there between. Referring again to FIGS. 9Aand 9B, enlarged cross sectional views of the system 110 show aplurality of strips of water-resistant pressure-sensitive seam sealant140 for sealing the joints or seams between adjacent panels 120. Seamsealant 140 may, as understood by one in art, consist of laminate,caulk, foam, spray, putty, or other mechanical means. Preferably, aplurality of strips of permeable tape 140 are used to seal seams betweenadjacent panels 120.

The permeability of the tape used at the seams can be altered for theclimatic zone (cold, mixed or hot/humid) and the building design used.In some climates in building designs, the tape may not need to bepermeable since adequate permeability is available through the buildingenvelope. In other climates in building designs, the tape will have tohave a high level of permeability such that the moisture escapes fromthe interior spaces of the wall, and mold, fungus, etc. is not supportedby the trapped moisture. Where a vapor barrier is required, the tapeused will have a permeance of less than 1.0 US Perm.

In one example, the tape 140 is polyolefin (polyethylene preferred)backing of a thickness of about 2.5 mils to about 4.0 mils Adhesive(butyl preferred) layered deposed on said backing is of a thickness ofabout 8.5 mils. to about 30 mils. Where a permeable barrier is required,the tape has water vapor permeance of greater than 1.0 US perm at 73°F.—50% RH via ASTM E96 procedure B) and possibly, as high as 200 USperms or more.

Whether the tape 140 is impermeable or permeable to water vapor, it mustbe able to resist liquid water from entering into the building envelope.Since the seam tape will need to seal against the liquid water astraditional house wraps do, it is reasonable to require the tape to meetstandards currently employed to measure liquid water penetration throughhouse wraps, as would be readily known by one skilled in the art.

The technologies that are used to make films or fabrics with water vaporpermeance greater than 1.0 US Perm are well known. Tapes that have highpermeance are often used in medical applications. Permeable tapes aremade from a variety of processes and such tapes may be made bonding apressure sensitive adhesive to a permeable layer. To improve strength,the permeable layer may be bonded to a woven or non-woven backing. Tapesmay have in their structure permeable fabrics, coatings, membranes, orcombinations thereof.

According to the preferred construction of the invention, theinstallation method 150 is shown in FIG. 10. The panels 120 are attachedto the exterior facing sides of the building frame 115. The attachmentpattern may be edge to edge, tongue-and-groove or any other appropriateconstruction alignment. Conventional fastening means such as nails,ring-shank nails, screws, or approved fastening means are used to attachthe panel 120 to the frame 115. According to the invention, thestructure is sealed by injecting, spreading or otherwise applying 157 amoisture proofing seam sealant to each seam between adjoining panels 120so as to create an impervious seam. There is no need for the seamsealant to be flush with the exterior major panel surfaces or to bind itinto the gap between the panels. Rather it is suggested that the seamsealant be applied over the exterior surfaces as shown in FIGS. 9A and9B to assure that a sufficient seal occurs given possible panel thermalor strain cycling with changes in temperature or humidity. The seamsealant is of various lengths as required for the building.

The presently described panels may also comprise a radiant barriermaterial attached to the lower face of the panel, i.e., the face of thepanel facing inwardly, toward the interior of the building. The radiantbarrier material has a reflective surface that reflects infraredradiation that penetrates through the roof back into the atmosphere. Thecombination of this reflective function, as well as the foil's lowemissivity, limits the heat transfer to the attic space formed in theinterior of the building in the space under the roof. By limiting theheat transfer, the attic space temperature is reduced, which in turnreduces the cost of cooling the house.

The radiant barrier material may simply be a single layer radiantbarrier sheet, such as metal foil, such as aluminum foil. Alternatively,the radiant barrier material may be composed of a radiant barrier sheetadhered to a reinforcing backing layer made from a suitable backingmaterial, such as polymeric film, corrugated paper board, fiber board orkraft paper. The backing material makes the foil material easier andmore convenient to handle. The multi-layered material may be a laminatein which a backing material is laminated to a radiant barrier sheet. Yetfurther alternatively, the radiant barrier may be a coating.

Both the radiant barrier material and the barrier layer can be appliedto the panel by spreading a coat of adhesive to the surface of thepanel, applying the heat-reflecting material (or the barrier layer) overthe adhesive onto the panel and pressing the radiant barrier material(or barrier layer) onto the panel. After the adhesive dries or cures,the panel is ready for use.

Another embodiment of the panel of the present invention is a panel,useful for roof and wall sheathing, that has improved friction undersome common conditions normally found on construction sites.Specifically, the panel of the presently described embodiment wasdesigned to achieve improved skid-resistance. As described previously,when installing a roof, it is very important that the surface of thesheathing panels need to have sufficient skid resistance so that aperson exercising reasonable care can work on the angled surfaces of theroof without slippage.

Although preferable for panels to remain dry during installation, on aconstruction site, the panels can be subject to moisture or wetness orhave sawdust or other foreign materials deposited on their surface,which can reduce the coefficient of friction (CoF) and result inundesirable slippage. Sawdust is especially common on panel surfaces aspanels often need to be cut to fit the roof properly. Sawdust can be asignificant problem as it may cause a reduction in the coefficient offriction of the sheathing panel surfaces. Accordingly, it is desired toremove as much sawdust as possible from the panel surfaces prior towalking thereon. Although construction workers may take some efforts toclean the sawdust off the surface of the panels using a broom, tappingthe board while on the edge, or using a leaf blower, these measuresoften prove to be inadequate. Specifically, these sawdust removalmethods do not always completely remove the sawdust from the surface.Accordingly, a panel that restores adequate skid-resistance afterremoving as much sawdust as possible using any suitable means or methodsuch as those described above is desired.

Improved performance after the removal of sawdust was achieved in eitherof two ways. The first method of improving performance and retainingadequate friction after the removal of sawdust is to use a saturatingresin in the barrier layer which has a slightly higher fraction ofvolatiles. The percent volatiles can be a relative reflection of theaverage molecular weight of the saturating resin. Accordingly, a slightchange in the percent volatiles can result in a measurable change in thedepth of embossing achieved in the final cure. For example, about a 6%increase in volatiles (as measured in the present experimentation from3.5% to about 3.7% of the total weight of the resin-saturated paper,including the glueline) resulted in improved embossing in that themeasured depth of at least some of the embossed features was measured tobe deeper. A thorough discussion of the overlay technology, includingthe measurement of volatiles, is found in U.S. Pat. No. 5,955,203.

The second method of improving the frictional characteristics of thepanel after the removal of sawdust was to change the type of woodfurnish used to manufacture the paper in the paper overlay. It wasdiscovered that changing the furnish used in the manufacture of thebarrier layer from the typically used hardwood species to softwoodspecies improved the retaining of friction after removal of sawdust.

To measure the friction in the presence of sawdust for the presentembodiment, the coefficient of friction was measured using the EnglishXL Tribometer. The standard techniques for using this equipment aredescribed in ASTM F1679-04 and “Pedestrian Slip Resistance; How toMeasure It and How to Improve It.” (ISBN 0-9653462-3-4, Second Editionby William English). The standard methods were used to compare thevarious test surfaces and conditions. To test the sheathing panels withsawdust, the amount of sawdust deposited on the surface of a panel neara saw cut was measured. The sawdust deposited on a panel surface wasmeasured by placing sheets of paper on the surface of a panel and makingcuts at the edge of the paper using a circular saw with a new blade. Theamount of sawdust produced by the saw was under these conditions was 2.5g/ft². The sawdust had a size distribution as shown in Table 6 (Runs1-4: 20 g samples; Run 5: 60 g sample; all 15 min. on vibration screenshaker.) That amount of sawdust was applied to and spread across thetest specimen surface evenly as possible, then the CoF was measuredusing the English XL Tribometer. The sawdust was removed by tilting onits edge and tapping it with a hammer to “knock” the sawdust off and thespecimen's CoF in this state was then measured. The wet condition wasmeasured according to the procedure described at pg. 173 in “PedestrianSlip Resistance; How to Measure It and How to Improve It.” Since CoF canchange depending on the surface, water was added in doses of about 1.54g of water per test strike until the CoF remained constant. The CoF wasmeasured for several configurations of sheathing panels and compared toexisting sheathing materials as controls. The data are reported in Table5.

The overlay panel has a texture on the surface that imparts asatisfactory CoF on the exterior surface of the panel. As describedpreviously in the prior described panel embodiment, the texture resultsfrom pressing a screen into the surface of the panel and comprised majorchannels and minor indentations. The screen pattern is not symmetric,but has large channels that are roughly orthogonal to much smallerchannels that are inside the larger channels. Ideally, the largerchannels run up and down and the smaller channels run side to side whenthe panel is installed on a roof. It was found that a small differencein CoF was measured depending on the test direction. The average of fourmeasurements (N, E, S, and W) is reported and the testing shown in thefollowing tables was initiated so that the first measurement was takenwith respect to the textured surface. N and S is measured along thedirection of the major channels and E and W is measured generallyorthogonally with the major channels. It was noted that some very smalldifferences in CoF could be measured depending on the axis (N-S vs. E-W)along which the measurements were taken. It is also expected that theconditions under which the test is conducted will have some affect onthe measured CoF. Variations in temperature and humidity may also havean affect on the measured CoF.

The texture preferably has a number of features or elements disposed ina first direction and a number of features or elements disposed in asecond direction. These elements or features disposed in first andsecond directions may be of similar or may be of different sizes. Theelements similarly may be of different or of similar shapes.Non-limiting examples of similarly sized features include a embossedherringbone or a embossed basketweave configuration. A herringbonepattern may be very tightly disposed or may be somewhat “spread-out” insuch a manner so that major channels with minor indentations arecreated.

The embossed textured surface preferably is more preferably comprised ofa plurality of major or primary textured features and a plurality ofminor or secondary textured features. Although the general appearance ofthe preferred textured surface 35 appears to be a random pattern ofraised areas, however, a closer examination of the preferred texturedsurface reveals finer detail. Specifically, the preferred texturedsurface 35 includes a plurality of major channels 33 that are disposedsubstantially parallel with a pair of opposing edges (preferably theshorter pair of opposing edges) of the panel. Additionally, a pluralityof minor indentations 34 are disposed within the major channels 33 andrun generally orthogonally to the major channels. Although it is withinthe scope of the present invention to provide for advantageousslip-resistance by providing any number of major channels, preferably,the density of the major channels is about 5 to about 15 major channelsper inch as measured in a direction perpendicular to the direction ofthe major channels. More preferably, the density of the major channelsis about 9 to about 12 major channels per inch as measured in adirection perpendicular to the direction of the major channels. On atypical 4′×8′ sheathing panel, the major channels will preferably rungenerally across the four-foot or short direction. It should beappreciated that it is not necessary nor required that the majorchannels be exactly parallel and may undulate slightly from side to sidein a somewhat serpentine fashion rather than being straight.

Although it is within the scope of the present invention that the minorindentations 34 may vary in length and width, the minor indentations 34have a preferably elongated shape that measures preferably about 0.0508cm (0.020 inches) to about 0.254 cm (0.100 inches) in length and about0.0254 cm (0.010 inches) to about 0.254 cm (0.100 inches) wide. Althoughit is within the scope of the present invention to provide foradvantageous slip-resistance by providing any number of minorindentations, preferably, the density of the minor indentations is about15 to about 35 of the minor indentations per inch as measured along thedirection of the major channels. The long direction of the minorindentations preferably extends generally across the eight-foot (orlong) direction of a typical panel.

In accordance with the preferred configuration of the textured surface35, in a typical roof sheathing application using 1.219 m×2.438 m(4′×8′) panels where the eight-foot edge of the sheathing panel isparallel to the floor of the home, the major channels 33 will generallybe oriented up and down, while the long direction of the minorindentations 34 will generally run across the roof. Preferred depth ofthe major channels and minor indentations have been found to be in arange of about 5 to about 35 mils as measured by the Mitutoyo SurfaceProfiler. It should be appreciated that at least some of the majorchannels and minor indentations may be of a depth greater or deeper thanthe thickness of the paper (i.e. some of the major channels and minorindentations may be of a depth that would project into the surface ofthe panel).

For preparation of the test panels for the presently describedembodiment, the overlay papers were bonded to mats in a primary processeither in the lab or on the regular manufacturing line. Then, testspecimens were cut from these panels. The conditions used to prepare thetest panels in the laboratory were approximately: Press time: 5 minutes;Press temp: 200° C.; panel dimensions: 40.64 cm×40.64 cm×1.27 cm(16″×16″×0.5″) thick; target density: 41.5 pcf; wood species: mixturesof pine; resin loading: face; MDI @ 4%; PPF @ 2% Core; MDI @ 4.5%; andwax loading: 2%.

TABLE 5 The CoF data for improved sheathing panels. Average N-S E-WSpecimen Condition CoF CoF CoF Softwood Dry 0.83 0.79 0.87 overlay paperWet 0.77 0.76 0.78 Sawdust 0.48 0.47 0.47 After Sawdust 0.85 0.77 0.92High volatiles Dry 0.83 0.79 0.86 overlay Wet 0.82 0.83 0.81 Sawdust0.42 0.41 0.43 After Sawdust 0.83 0.80 0.85 OSB Dry 0.86 0.84 0.87 Wet0.80 0.80 0.80 Sawdust 0.54 0.51 0.58 After Sawdust 0.72 0.73 0.71Plywood Dry 1.0 >1 >1 Wet 0.84 0.83 0.85 Sawdust 0.53 0.54 0.52 AfterSawdust 0.62 0.61 0.63

The measurements in Table 5 were taken under conditions of highertemperature and humidity as compared with earlier described testingconditions.

TABLE 6 Particle size distribution of sawdust used to measure CoF. SieveOpening size No. (in microns) Run #1 Run #2 Run #3 Run #4 Run #5 18 10000.19 0.21 0.19 0.18 0.47 30 600 0.6 0.83 0.68 0.58 2.17 60 250 3.44 4.573.42 3.40 9.90 80 180 3.53 3.15 2.98 2.72 8.76 100 150 1.30 2.52 4.281.17 3.10 140 106 4.71 5.13 3.23 2.32 9.78 200 75 1.12 1.54 1.79 2.286.48 325 45 4.07 1.55 4.11 3.87 10.79 pan 0 0.57 0.07 1.92 2.97 8.00

While the present invention has been described with respect to severalembodiments, a number of design modifications and additional advantagesmay become evident to persons having ordinary skill in the art. Whilethe illustrative embodiments have been described in considerable detail,it is not the intention of the applicant to restrict or in any way limitthe scope of the appended claims.

What is claimed is:
 1. A panel system to externally envelope astructure, the system comprising: at least two adjacent lignocellulosicpanels, each panel including an outer surface, an inner surface, and atleast one edge extending therebetween, wherein each panel is alignedwith its at least one edge proximate to the at least one edge of theadjacent panel to define a longitudinal joint between the two adjacentpanels, and wherein the edges of the adjacent panels are substantiallyparallel to each other; a barrier layer secured to the outer surface orthe inner surface of each panel, the barrier layer being substantiallybulk water resistant and substantially water vapor permeable; and a bulkwater resistant edge sealant sealing the joint between the proximateedges of the two adjacent panels, wherein the edge sealant includesstrips of water-resistant tape having an adhesive layer and a backing,wherein the assembled panel system forms a sealed wall or roof of thestructure without applying a separate moisture barrier layer of housewrap or felt paper.
 2. The system of claim 1, wherein each panel andbarrier layer has a water vapor transmission rate from about 0.7 toabout 7 grams/m²/24 hrs as determined by ASTM E96 procedure A (at 73°F.—50% RH) and a liquid water transmission rate from about 1 to about 28grams/100 in²/24 hrs via Cobb ring according to the test methoddescribed in ASTM D5795.
 3. The system of claim 1, wherein the panelincludes alignment guides for application of the water-resistant tape.4. The system of claim 1, wherein the tape backing includes a polyolefinmaterial.
 5. The system of claim 1, wherein the tape includes a watervapor permeance of greater than 1.0 perm as determined by via ASTM E96procedure B (at 73° F.—50% RH).
 6. The system of claim 1, wherein theedge of one of the panels is a tongue and the edge of the adjacent panelis a groove.
 7. The system of claim 1, wherein an outer surface of thebarrier layer is textured.
 8. The system of claim 7, wherein thetextured outer surface provides a wet coefficient of friction in a rangeof about 0.8 to about 1.1 (English XL Tribometer) and a dry coefficientof friction of at least about 0.8 (English XL Tribometer).
 9. The systemof claim 1, wherein the edge sealant includes a liquid sealant.
 10. Apanel system to externally envelope a structure, the system comprising:at least two adjacent lignocellulosic panels, each panel including anouter surface, an inner surface, and at least one edge extendingtherebetween, wherein each panel is aligned with its at least one edgeproximate to the at least one edge of the adjacent panel to define alongitudinal joint between the two adjacent panels, and wherein theedges of the adjacent panels are substantially parallel to each other; abarrier layer secured to the outer surface or the inner surface of eachpanel, the barrier layer being substantially bulk water resistant andsubstantially water vapor permeable, wherein the barrier layer includesa resin-impregnated paper substantially covering the outer surface ofthe panel, the resin-impregnated paper having a paper basis weight of21.772 kg (48 lbs.) to about 102.058 kg (225 lbs.) per ream and a resincontent of less than 80% by dry weight; and a bulk water resistant edgesealant sealing the joint between the proximate edges of the twoadjacent panels, wherein the edge sealant includes strips ofwater-resistant tape having an adhesive layer and a backing, wherein theassembled panel system forms a sealed wall or roof of the structurewithout applying a separate moisture barrier layer of house wrap or feltpaper.
 11. A method of externally sheathing a building structure, themethod comprising: obtaining at least two panel assemblies, each panelassembly including a lignocellulosic panel including an outer surface;an inner surface; and at least one edge; and a barrier layer secured tothe outer surface of each panel, the barrier layer being substantiallybulk water resistant and substantially water vapor permeable;positioning the panel assemblies adjacent to each other such that therespective edges are proximate and substantially parallel to each otherto define a longitudinal joint therebetween and such that the respectiveinner surfaces contact the structure; fastening each panel assembly tothe structure; and sealing the joint between the edges of the panels byapplying strips of adhesive-backed water-resistant tape to one of theouter surface and the barrier layer, including removing a backing toexpose an adhesive layer and applying the adhesive layer to the adjacentpanels covering the longitudinal joint, wherein the resulting assembledsealed panel system forms a sealed wall or roof of the structure withoutapplying a separate moisture barrier layer of house wrap or felt paper.12. The method of claim 11, wherein the barrier layer includes aresin-impregnated paper substantially covering the outer surface of thepanel, the resin-impregnated paper having a paper basis weight of 21.772kg (48 lbs.) to about 102.058 kg (225 lbs.) per ream and a resin contentof less than 80% by dry weight.
 13. The method of claim 11, wherein eachpanel assembly has a water vapor transmission rate from about 0.7 toabout 7 grams/m²/24 hrs as determined by ASTM E96 procedure A (at 73°F.—50% RH) and a liquid water transmission rate from about 1 to about 28grams/100 in²/24 hrs via Cobb ring according to the test methoddescribed in ASTM D5795.
 14. The method of claim 11, wherein the edge ofone of the panels includes a tongue, the edge of the adjacent panelincludes a groove, and the step of positioning each panel along thestructure includes positioning the tongue proximate the groove.
 15. Themethod of claim 11, the step of positioning each panel along thestructure includes positioning the edge of one of the panels a distanceaway from the edge of the adjacent panel to allow for expansion andcontraction of each panel.
 16. The method of claim 11, wherein sealingthe joint between the edges of the panels includes applying a liquidsealant to one of the outer surface and the barrier layer.